What's the brand and model of your isolation trans? I want to keep it in my back pocket.

Thx

The one I am using is a 13amp unit made by Leviton and the model I using is no longer available. Got it new real cheap at $50 and works just fine. Tripp Lite makes some Isolation Transformers that is easy to find. The problem withTripp Lite isolation transformers is that they tied the neutral to ground not a complete isolation unless you use their HG models like the IS1800HG or IS1000HG.

I forget the model of Tripp-Lite isolation transformer, but it didn't work for my with my tube amp. Want to say a 250 something or other. Have to dig it up from amazon. I feel my issues are a 50 year old house with commensurate ground/wiring. Do hope the house I move into toward end of December, which is brand new construction, doesn't have such problems. But my hand MCM will be ready if needed.

I've had various hum/buzz issues with amps over the years. Only of late have I decided it was time to do something about it. I love the silence now! Don't live with the hum/buzz.

A mis-wired outlet can cause grief. For example, the black and white wires are reversed, the ground is not hooked up, etc. There are a bunch of conditions listed on the test device above, all should be checked. If anything tests bad, call an electrician to get it fixed. Alternately, you can turn off your house power and check the wiring in the outlet yourself, if you know something about electricity. But since I'm writing this, I'm guessing that's probably not the case. So call an electrician.

Next thing to do: get a voltmeter, set it to measure AC first (then DC), then check to see if there is any voltage between the chassis of the noisy device, and a ground. By a ground, I mean for example, a plumbing fixture in the house. You can also test against the electrical ground in an outlet, if you know what you're doing (but I advise against sticking any sort of probe into an AC outlet unless you are very familiar with electricity). If you measure any voltage at all, call an electrician. You have a wiring problem in your house that requires attention. Do not attempt to fix this yourself.

Where I live, a lot of the homes were built in the mid to late 1950's (about the same vintage as the tubes we like to buy). The standards for wiring back then, are not what they are today. Wiring can break down, insulation can stop insulating, or previous owners of the homes could have done stupid crap with the house wiring. I've gone through and fixed many issues in my own house due to the stupidity of previous owners. I'm amazed that people don't hurt themselves more often with bad wiring.

Once you're convinced that your wiring is ok, and you still have noise, then get a power conditioner.

Would it only hum when the lights were on, or when they were off as well?

The one in my dining area (apartment) emits a slight glow even when switched off, but doesn't emit any noise from the switch unless it's turned on. So, ymmv, depending on the switch and what circuit it's on.

The wiring in my place is fairly dodgy anyway. When the upstairs neighbor uses the 'facilities' it rattles the wiring enough to cause a popping sound from my speakers.

A mis-wired outlet can cause grief. For example, the black and white wires are reversed, the ground is not hooked up, etc. There are a bunch of conditions listed on the test device above, all should be checked. If anything tests bad, call an electrician to get it fixed. Alternately, you can turn off your house power and check the wiring in the outlet yourself, if you know something about electricity. But since I'm writing this, I'm guessing that's probably not the case. So call an electrician.

Next thing to do: get a voltmeter, set it to measure AC first (then DC), then check to see if there is any voltage between the chassis of the noisy device, and a ground. By a ground, I mean for example, a plumbing fixture in the house. You can also test against the electrical ground in an outlet, if you know what you're doing (but I advise against sticking any sort of probe into an AC outlet unless you are very familiar with electricity). If you measure any voltage at all, call an electrician. You have a wiring problem in your house that requires attention. Do not attempt to fix this yourself.

Where I live, a lot of the homes were built in the mid to late 1950's (about the same vintage as the tubes we like to buy). The standards for wiring back then, are not what they are today. Wiring can break down, insulation can stop insulating, or previous owners of the homes could have done stupid crap with the house wiring. I've gone through and fixed many issues in my own house due to the stupidity of previous owners. I'm amazed that people don't hurt themselves more often with bad wiring.

Once you're convinced that your wiring is ok, and you still have noise, then get a power conditioner.

Thanks for the comprehensive advice. I'll see if I can hunt down a tester today. Also going to try changing out the interconnects to see if there's any change.

OK - I've changed the interconnects - no difference - even ran the left channel through one and the right through another and there was no discernible difference in level - given that they were widely differing in quality, I'm guessing I can cross those off as a problem...

didn;t get a chance to grab a tester today, but I might do that first thing tomorrow, then if that confirms the socket is ok, I'm off to get a power conditioner...